1. Field of the invention
This invention relates to electronic still cameras, and more particularly to an electronic still camera wherein a subject is photographed by an image sensing device such as a solid state image sensing device and an image signal thereof is recorded into a rotary recording medium such as a magnetic disc.
2. Description of the Prior Art
Recently, there has been developed an electronic still camera system wherein an image sensing device such as a solid state image, sensing device or an image pickup tube is combined with an inexpensive recording device using a magnetic disc as a recording medium and yet having a comparatively high memory capacity, wherein a subject is still-photographed electronically and recorded into a rotating magnetic recording medium, and the reproduction of an image is carried out by a television system, a printer and the like, which are provided separately.
In the above-described electronic still camera, an optical finder is used as a finder. When a subject is photographed by use of an electronic still camera, with the subject being identified by the optical finder, image information of the subject recorded on a recording medium such as a magnetic disc does not actually coincide with subject information recognized by the naked eye through the optical finder due to the characteristics of the solid state image sensing device such as a charge coupled device (CCD) or due to the limit in the number of the picture elements of the solid state image sensing device. As a consequence, when a photographer looks at a reproduced image, normally he has a feeling of unusualness to an extent.
On the other hand, in contrast to the optical finder, there is an electronic view finder which electrically displays an image of the subject on a display screen by use of the image information of the subject recorded on the recording medium.
As a consequence, the image of the subject identified by the electronic view finder is identical with an image reproduced from the image information actually recorded into the recording medium, so that the image of the subject recorded can be identified as it is by the finder.
However, the electronic view finder has such drawbacks that it needs an adapter for the specific purpose, and is expensive as compared with the optical finder. Accordingly, if such an arrangement of the electronic view finder mountable to the electronic still camera equipped with the optical finder is used, then it will be very convenient.
Furthermore, when the electronic still camera is equipped with an adapter to be converted into a system for use as a movie camera, such an arrangement should be adopted that a movie adapter as an interface to the main body of the camera is equipped, whereby a photographing mode is changed over from a normal mode for still-photographing by use of the optical finder to a movie camera mode for photographing by use of the electronic still camera as a movie camera.
There has heretofore been the conventional electronic still camera which permits photographing in the normal mode and the movie camera mode. However, there has been no electronic still camera, wherein, during photographing, the normal mode can be changed over to a movie still mode for still-photographing by use of the electronic still camera equipped with the movie adapter and for outputting the video signal thereof to the outside.
Further, in the conventional electronic still camera, start of a spindle motor as being means for rotatably driving a rotary magnetic recording medium such as a magnetic disc is performed by a release switch operationally associated with a shutter release button. As a consequence, when the release switch repeats the ON-OFF operation within a short period of time due to the operations of the shutter release button, the spindle motor also repeats starts and stops.
When the spindle motor is restarted after the start as described above, there is presented such a problem that the power consumption is increased.
Furthermore, in order to record the image signal into the rotary magnetic recording medium such as a magnetic disc at a field or frame rate, it is necessary to perform high speed rotation at a constant speed as will be described hereunder. As a consequence, when the start and stop of the spindle motor are repeated, there is a problem that excessive time is needed until a predetermined rotation number required for recording the image signal is reached, whereby there is a possibility of losing shutter chances.